The "Gleeful Flames" deck has a single-minded focus: deal 20 damage to your opponents before they deal 20 to you. You have twelve spells that each deal 5 damage, and it only takes four of them to win the game.

Concentrate on reducing your opponent's life total, not on protecting your own. Your goal is to set yourself up to win when you draw your next explosive spell. Artillerize and Goblin Grenade require you to sacrifice a creature to cast them so be cautious about committing your creatures to combat. Don't block until you have enough mana to sacrifice your creature to an Artillerize before it dies or to cast a Brimstone Volley after combat. Your opponent's creatures will probably survive, but you'll be one step closer to winning.

The creatures in this deck aren't going to win the game on their own, but they do a great job of supporting your burn spells. Most of the creatures are Goblins that can be sacrificed to cast Goblin Grenade, the least expensive of your 5-damage spells. Goblin Arsonist and Goblin Fireslinger sneak in some extra damage to your opponent outside of combat. Forge Devil isn't a Goblin, but the 1 damage it deals to a creature when it enters the battlefield will often disrupt your opponent's game plan by taking down a Llanowar Elves or Birds of Paradise.
Of course, every 5 damage your creatures can deal to your opponent is another burn spell you don't have to draw. Be sure to attack whenever the way is clear. Equipping one of your creatures with Infiltration Lens and attacking with it is a win-win situation for you: If it isn't blocked, your opponent's life total gets smaller. If it is blocked, you draw two cardsand more cards means more damage-dealing spells!

Your sideboard lets you slow down your opponents, giving you more time to draw into your key cards. Bring in Dismember against decks with a few big creatures. You'll need to pay 4 life to cast it, but that's better than getting run over by a giant monster. Arc Trail and Gut Shot are great against fast decks that rely on small creatures. Into the Core is an obvious choice against decks trying to win with artifacts.

When you're ready to customize this deck, just add your favorite flavors of fiery destruction. If you want a more controlling deck, Chandra's Phoenix and Chandra, the Firebrand, both from the Magic 2012 core set, work well with all your burn spells. If you want even more burn spells, Incinerate and more Gut Shots are great options. If you want to send your creatures on the attack early on, you could try adding Stormblood Berserker and Porcelain Legionnaire.